Conventionally, a semiconductor device employing silicon carbide (SiC) has been known (for example, see international publication WO01/018872 (hereinafter, referred to as “Patent Literature 1”)). In Patent Literature 1, a SiC substrate of 4H polytype having a plane orientation of substantially {03-38} is used to form a MOS field effect transistor (MOSFET; Metal Oxide Semiconductor Field Effect Transistor) serving as the semiconductor device. In this MOSFET, a gate oxide film is formed by means of dry oxidation. Patent Literature 1 describes that such a MOSFET can achieve a large channel mobility (approximately 100 cm2/Vs).